Influence of long-term dynamic load induced by high-speed trains on the accumulative deformation of shallow buried tunnel linings

The accumulative deformation of shield tunnels is a serious threat to long-term safety of metro tunnels. In the case of metro tunnels crossing underneath high-speed railways (HSR), although the long-term dynamic load of high-speed trains (HST) is small, which can still induce dynamic response of the tunnel linings underneath HSR, thereby causing accumulative deformation of the tunnel structure. With the aim of investigating the effect of long-term dynamic load of HST on the accumulative deformation of tunnel linings underneath HSR, the present paper conducted a 1/10 scaled model experiment and numerical modelling based on the case of Guangzhou metro line 9 underneath Wuhan to Guangzhou passenger-dedicated HSR. The analysis of numerical modelling and physical model experiment results, in terms of the dynamic response of tunnel linings, the displacement of tunnel segments, diameter convergence of tunnel linings and the mechanism of accumulative deformation suggest that, the tunnel rings underneath HSR indeed go through an accumulative process, exhibiting tunnel invert shifts inwards. The deformation of the involved tunnel rings increases slightly at first and heavily later, attributing to the joint dislocation and opening. This paper reveals the influence of long-term dynamic load of HST on the accumulative deformation of the subjacent tunnels, which convinces us that the influence of long-term dynamic load induced by HST should be took into consideration in the design work of similar engineering cases.